GM Service Manual Online
For 1990-2009 cars only

Special Tools

J 21177-A Drum to Brake Shoe Clearance Gauge

Park Brake Shoe Adjustment

Warning: Refer to Brake Dust Warning in the Preface section.

  1. Apply and fully release the park brake lever.
  2. Verify that the park brake lever releases completely.
  3. Turn ON the ignition. Verify that the red BRAKE warning indicator lamp is off.
  4. Turn OFF the ignition.
  5. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  6. Remove the rear tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation.
  7. Note: Do not operate the park brake lever with the rear disc brake rotors removed.

  8. Remove the rear disc brake rotors. Refer to Rear Brake Rotor Replacement.

  9. Object Number: 177200  Size: SH
  10. Place the inside measurement contacts of the J 21177-A at the widest point of the drum portion of the brake rotor (1).
  11. Tighten the set screw on the tool in order to ensure the proper measurement when removing the tool from the drum.

  12. Object Number: 177201  Size: SH
  13. Position the outside measurement contacts of the J 21177-A over the park brake shoe (1) at the widest point.
  14. Note: If the gap between the adjuster nut and the adjuster screw exceeds 5 mm (0.25 in) during the adjustment procedure, the park brake shoe must be replaced.

  15. Adjust the park brake shoe-to-drum clearance by rotating the adjustment nut on the park brake actuator.
  16. Specification
    0.38 mm (0.015 in)

  17. Install the rear brake rotors. Refer to Rear Brake Rotor Replacement.
  18. Install the rear tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation.
  19. Apply the park brake lever. Inspect the rotation of the rear wheels:
  20. • The wheels should not rotate forward.
    • The wheels should drag or not rotate rearward.
  21. If the rear tire and wheel assemblies rotate forward or do not exhibit drag rearward, proceed to the park brake cable adjustment.
  22. Release the park brake lever. Verify that the wheels rotate freely.

Park Brake Cable Adjustment


    Object Number: 929729  Size: SH
  1. Remove the front floor console. Refer to Console Replacement.
  2. With the park brake lever in the fully released position, using ONLY hand tools, loosen the adjusting nut completely to the end of the front cable threaded rod.
  3. Raise the park brake lever 1 detent position.
  4. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 891460  Size: SH
  5. Using ONLY hand tools, tighten the park brake cable adjusting nut (1) until light to moderate drag is exhibited while rotating the rear wheels.
  6. Attempt to rotate the rear wheels. There should be no rotation forward or rearward.
  7. Fully release the park brake lever.
  8. Verify the park brake is released by rotating the rear wheels. The wheels should rotate freely and exhibit no park brake shoe drag.
  9. If the wheels do not rotate freely, repeat the park brake cable adjustment procedure.
  10. Raise the park brake lever 3 detent positions and attempt to rotate the rear wheels:
  11.  - One of the wheels should not rotate forward or rearward.
     - The other wheel should not rotate forward or rearward, or should require substantial effort to rotate.
  12. Install the front floor console. Refer to Console Replacement.
  13. Release the park brake lever.